The invention refers to a pharmaceutical composition having enhanced antitumor activity and/or reduced side effects.
A significant portion of antitumor agents (cytostatics) destroy tumor cells acting partially via inhibiting the synthesis of DNA and RNA, and partially via damaging the completed DNA. The known antitumour agents may seriously damage genes of healthy cells causing mutations and deletions both in the mitochondrial and the nuclear genoms. Antitumor agents often cause general cell damage besides their primary antitumor effect. This leads to side effects often making continuation of the treatment impossible, and even resulting in the death of patients. Therefore, the most critical part of antitumor treatment is the sensitivity of patient to the serious side effects of cytostatics.
Because of problems cited above, it is of great significance to produce pharmaceutical composition which possesses the antitumour activity of cytostatics or increased antitumor activity thereof without side effects or at least with reduced side effects.
The aim of the invention is to provide a pharmaceutical composition in which the activity of a known antitumor active substance is either enhanced, or said activity is retained and simultaneously the side effects of the known active substance are reduced.
Hydroximic acid derivatives of formula (I), 
wherein
R1 is hydrogen or C1-5alkyl group;
R2 represents hydrogen; C1-5alkyl group; C3-8cycloalkyl group; or phenyl group optionally substituted by hydroxyl or phenyl group; or
R1 and R2 together with the adjacent nitrogen atom form a 5 to 8 membered ring optionally containing additional nitrogen, oxygen or sulfur atom(s); and said ring can be condensed with an other alicyclic or heterocyclic ring, preferably with benzene, naphthalene, quinoline isoquinoline, pyridine or pyrazoline ring; furthermore if desired and it possible, nitrogen and/or sulfur as heteroatom(s) are present in the form of an oxide or dioxide;
R3 stands for hydrogen or phenyl, naphthyl or pyridyl group optionally substituted by one or more halogen(s) or C1-4alkoxy group(s);
Y is hydrogen; hydroxyl group; C1-24alkoxy group optionally substituted by amino group; C2-24poly-alkenyloxy group containing 1 to 6 double bond(s);
C1-25alkenoyl group; C3-9alkenoyl group; or a group of formula R7xe2x80x94COOxe2x80x94, wherein R7 is a C2-30polyalkenyl group containing 1 to 6 double bond(s);
X represents halogen; amino group; or C1-4alkoxy group; or
X and B together form an oxygen atom; or
X and Y together with the adjacent carbon atoms and the interjacent xe2x80x94NRxe2x80x94Oxe2x80x94CH2xe2x80x94 group form a ring of formula (a), 
xe2x80x83wherein
Z is oxygen or nitrogen;
R is hydrogen; or
R and B together form a chemical bond;
A stands for C1-4alkylene group or a chemical bond; or a group of the formula (b), 
xe2x80x83wherein
R4 represents a hydrogen; C1-5alkyl group; C3-8cycloalkyl group; or a phenyl group preferably substituted by halogen. C1-4alkoxy or C1-5alkyl group;
R5 stands for a hydrogen; C1-4alkyl group; or a phenyl group;
m is 0, 1 or 2; and
n is 0, 1 or 2 are known from the art.
The U.S. Pat. No. 4,308,399 discloses compounds belonging to the scope of hydroximic acid derivatives of formula (I), which are useful for treatment of the diabetic angiopathy.
The EP-PS No. 417,210 describes hydroximic acid halides, which also fall into the scope of compounds of formula (I), possess a selective xcex2-blocking effect and are useful for treatment of the diabetic angiopathy.
HU-PS published under No. T/66350 discloses a number of other hydroximic acid derivatives being within the scope of compound of formula (I). These known substances are useful in the therapy of vascular deformations, particularly of diabetes mellitus.
It is known from the PCT Patent Application published under No. WO 97/13504 that hydroximic acid derivatives of formula (I) are useful for the prevention and treatment of disorders of mitochondrial origin.
The aim of the present invention is to provide a pharmaceutical composition possessing the effect of the known cytostatic agent but exerting the side effects thereof to a decreased degree.